public class HRDepartment : Company{
    public HRDepartment(string name) : base(name){
    }

    public override void Add(Company company){
        // 透明模式，不实现
    }

    public override void Remove(Company company){
        // 透明模式，不实现
    }

    public override void Display(int depth){
        Console.WriteLine(new string('-', depth) + name);
    }

    public override void LineOfDuty(){
        Console.WriteLine($"{name} 员工招聘培训管理");
    }
}